diff --git a/src/LoginPacket.php b/src/LoginPacket.php
index 707571f9..e33cff8f 100644
--- a/src/LoginPacket.php
+++ b/src/LoginPacket.php
@@ -72,6 +72,10 @@ protected function decodeConnectionRequest(string $binary) : void{
 		if(!is_array($chainDataJson["chain"])){
 			throw new PacketDecodeException("Chain data 'chain' element must be a list of strings");
 		}
+		if(count($chainDataJson["chain"]) !== 3) {
+			throw new PacketDecodeException("Chain data 'chain' must contain three jwt");
+		}
+
 		$jwts = [];
 		foreach($chainDataJson["chain"] as $jwt){
 			if(!is_string($jwt)){